Werner Heisenberg

Context

Important Terms and People

Werner Karl Heisenberg was born on December 5, 1901, in Würzburg,
Germany. His father, August, was a professor of Greek philology,
his mother, Annie, an intelligent and caring homemaker. In many
ways, his family fit the typical bourgeois mold of the time, placing
an emphasis on respectability and social grace–values that Heisenberg
would soon begin to question. Also, at an early age, Heisenberg
was encouraged to compete, especially with his brother, which instilled
in him a drive to succeed that would characterize his entire career.
The brothers were encouraged to compete even in music, and Heisenberg
developed a lifelong passion for the piano, which often served
as a calming influence.

Heisenberg's formative years took place against the backdrop World
War I, and in the beginning he may have been caught up in romanticizing
warfare, though he would face inevitable disillusionment. After
the war, he and many of Germany's youth were left feeling lost
and confused. In response, Heisenberg joined various youth movement
groups that provided him with a sanctuary. The focus of these groups
was not activism; rather, it gave groups of boys the opportunity
to discuss philosophy, bond, and find new forms of idealism to
replace others that had been destroyed by the war. As a group leader,
Heisenberg served as a father figure for many younger boys, and
he continued to go on retreats into the 1930s.

The war had no small impact on Heisenberg's schooling:
he attended the elite Maximilians-Gymnasium, of which his grandfather
was rector. Many school resources were cut back and classes disrupted,
but Heisenberg managed to advance far beyond his curriculum, at
least in math and physics. After graduating with recognition as
one of the top students in Bavaria, he attended Munich and, almost
by default, ended up studying with Ernest Sommerfeld. Sommerfeld
was not only a great mentor who truly supported his students, but
he would lobby for Heisenberg throughout his career, naming him
as his heir apparent (though Nazi opponents would thwart this plan).

Under Sommerfeld, Heisenberg constructed his core model
of the atom, which answered many of the current puzzles while also discarding
cherished principles of quantum theory, including some of the work
of Sommerfeld and Niels Bohr. The model would have to be refined
considerably, but characteristics of it would find vindication
later. At Munich, Heisenberg also met Wolfgang Pauli, and the two
brilliant scientists clicked immediately, with much in common scientifically,
if not personally. The two would continue to correspond and criticize
each other's work throughout their careers.

In July 1923, Heisenberg received his doctorate, but only
with the lowest form of honors because he had performed miserably
in the experimental portion of his physics orals. Embarrassed,
he returned to Göttingen, where he had studied briefly with Max
Born during Sommerfeld's absence. There, Heisenberg formulated
his Zeeman principle, which earned him an invitation to Copenhagen to
meet with Bohr. He would later serve as Bohr's assistant, and the latter
would come to be probably the most significant intellectual influence
on Heisenberg.

In 1925, while at Copenhagen, Heisenberg published his
first paper laying the groundwork for his quantum mechanics. On receiving
a copy of the paper, Max Born almost immediately saw that Heisenberg's
multiplication of amplitudes involved a rule used in matrix multiplication–an
area of mathematics to which few scientists were exposed. Months
later, Born, Heisenberg, and Jordan coauthored the paper that established
matrix mechanics, but their work was soon rivaled by a new approach
developed by Erwin Schrödinger. Schrödinger treated the matter
as waves rather than particles, and he was able to derive the same
results with wave mechanics as Heisenberg had with matrix mechanics.
Heisenberg acknowledged the mathematical advancement that Schrödinger's work
contributed, but he refused to accept the completely different picture
of the atom that the work entailed.

With Schrödinger's work gaining popularity–as physicists
preferred his mathematical method–Heisenberg again captured the world's
attention with his formulation of the uncertainty principle. He
argued that it was impossible to determine both the exact position
and velocity of a particle, as the act of seeing the particle with light
necessitated a disturbance. Bohr responded with his complementarity
principle, which provided an extension of Heisenberg's work, while
Einstein reacted with complete disapproval of both principles,
insisting on the attainability of determinism. Nevertheless, the
impact of Heisenberg's work was unquestionable, and he soon became
Germany's youngest full professor at Leipzig.

It was not long before the onset of the Nazi regime, as
Hitler came to power in 1933. Heisenberg, throughout his career,
believed in the separation of science and politics, and refused
to commit either for or against the Third Reich. He made the oft-criticized choice
to stay in Germany, despite the resignation and flight of many
of his celebrated colleagues. He would also participate in Germany's
nuclear weapons project, but he never believed the bomb would be
attainable for use in the war. When Heisenberg learned that the
Americans had in fact succeeded in building a bomb, he became very
defensive, not only about himself, but also the state and capability
of German physics in general.

After the war, Heisenberg spent much of his time on science
policy rather than his own research. He would publish a few more papers
but also focused on trying to ensure his place in the intellectual
tradition, knowing that he had already made his most important
contributions. Heisenberg passed away in his Munich home on February
1, 1976, after a battle with cancer.